Overview, Background, Timeline And History Of CTE
Chronic traumatic encephalopathy (CTE) is the term used to describe brain degeneration likely caused by repeated head traumas. It is also noteworthy that NFL athletes do not appear to have an increased risk of suicide compared with the general population (data suggest a decreased risk), 95 , 96 casting some doubt on the inference that concussive or subconcussive exposure leads to heightened suicidality.
The CTE stage correlates with the progression of clinical symptoms, and among American football players the stage of CTE at death significantly correlates with age at death, number of years playing football, and number of years after retirement from football 29 However, it remains unclear whether all cases progress, and progress at similar rates, or whether some instances of CTE persist indefinitely as early-stage disease.
For instance, MRI based techniques such as diffusion tensor imaging (DTI) have been used to identify axonal injury and white matter abnormalities, which have been related to CTE progression 55 Additionally, PET imaging has been developed to observe pathologic proteins such as p-tau in living brains 56 Fluid biomarkers targeting substances in the CSF or peripheral blood have also been examined 57 Peripheral blood represents an attractive target for biomarkers due to relative ease of obtaining from living individuals and the increased quantity compared to the CSF.
While CTE is associated with tauopathy, the existence of CTE as a distinct neuropathologic condition is not universally accepted 4, as other neurodegenerative conditions are associated with the presence of abnormal tau proteins 5, and abnormal tau protein deposition has been reported to be part of the normal aging process in the absence of head trauma 5, 6. As of 2013, there were 158 cases of CTE reported in the published literature 4. While the authors of these studies propose that both concussive head injury and repetitive subconcussive impacts lead to neuropathologic changes and the subsequent development of CTE neuropsychiatric symptoms, behavioral changes, and cognitive deficits of CTE 4, 7, the sample sizes of these studies are very small and contain an element of selection bias.
The term chronic traumatic encephalopathy” (CTE) was coined in 1957 2 but did not achieve wide recognition until its revival in 2005 when Omalu and colleagues 3 used CTE to describe a progressive tauopathy affecting the post-mortem brains of professional American football players.
Tau and neurofilament light chain (NF-L) 62 have been used as potential measures of axonal injury while S100β and GFAP have been reported to be elevated following contact sports play 63 Ultimately, no one biomarker may be adequate for proper identification of CTE.
Others, including military veterans who've had a head injury, are also vulnerable to the disease. A common topic of concern is concussion, or mild traumatic brain injury, in young athletes and whether concussions sustained at a young age could lead to lifelong impairment such as chronic traumatic encephalopathy (CTE).
The symptoms of CTE include memory loss, confusion, impaired judgment, impulse control problems, aggression, depression, anxiety, suicidality, parkinsonism, and, eventually, progressive dementia. Studies of football players show repetitive head blows have led to chronic traumatic encephalopathy, which kills brain cells and causes aggression, depression or dementia.
Traditionally, concussions were considered benign events and although most people recover fully, about 10% develop a post-concussive syndrome with persisting neurological, cognitive and neuropsychiatric symptoms. Savica R, Parisi JE, Wold LE, Josephs KA, Ahlskog JE. High school football and risk of neurodegeneration: a community-based study.
When the same symptoms started showing up in retired professional football players, researchers became interested and examined the brains of these men after their deaths. Unfortunately, this study did not specifically examine if the levels of tau deposits and number of concussions were related to presentation of depressive symptoms.
Brain damage in boxers: a study of the prevalence of traumatic encephalopathy among ex-professional boxers. But the brains of some other players found to have the disease — like Junior Seau, Mike Webster and Andre Waters — were examined elsewhere. Gill also pointed out that a law passed in 2009 — the Zackery Lystedt Law — requires school districts and nonprofit organizations using school facilities to adopt policies for the management of concussion and head injury in youth sports.
The difference is that the tau protein builds up in the wrinkles of the brain in those affected with CTE, while in those affected with Alzheimer's, the protein is more spread out in the brain. Some parts of the brain show tangles of tau protein We all have tau protein, but it forms tangled fibers in CTE and in certain other neurodegenerative diseases, like Alzheimer's.